The present invention is directed to a hand tool with a shifting gear unit containing gears arranged on an output drive shaft. The gears can be selectably coupled by a connecting or shifting device with the output drive shaft so that the gear rotates the shaft. The connecting or shifting device includes a slide actuatable by a rotatable handle.
Hand tools, such as motor driven drills, often contain a gear box for providing different operating speeds or different functions. As an example, DE-PS 1 602 712 discloses a drill with a two-speed gear shift. This known drill has a connecting or shifting device for selectively coupling one of two gears with an output drive shaft so that the gears are fixed to and rotate the shaft. The shifting action is effected by a slide. The slide forming a part of the shifting device is actuated by means of a rotatable handle. A drive cam, arranged eccentrically relative to the axis of rotation of the handle, engages a closed slot in the slide for displacing the slide. As a result, rotation of the handle leads to a displacement of the slide. The selected shifting position is maintained by means of a ball catch cooperating with the handle.
This known hand tool has the disadvantage that the handle displaces the slide only along a small path corresponding to the eccentric arrangement of the drive cam, whereby this known arrangement is not suitable for shifting a multiple-speed gear unit with a correspondingly larger displacement path. Means for providing larger displacement paths, known from other technical fields, are susceptible to disturbances in that they are unsuitable for use in hand tools of the type to which the present invention is directed.